SEQUENCE COMPARISONS OF THE INTERNAL TRANSCRIBED SPACER REGION OF RIBOSOMAL GENES SUPPORT CLOSE RELATIONSHIPS BETWEEN PARASITIC ANTS AND THEIR RESPECTIVE HOST SPECIES (HYMENOPTERA, FORMICIDAE)

A fragment of the internal transcribed spacer (ITS-I) adjacent to the 5.8S rRNA gene of 20 myrmicine ant species was sequenced. Sequence com parisons were carried out between 11 species of the tribe Leptothoraci ni, five species of the tribe Tetramoriini, three species of the tribe Solenopsidini and one species of the tribe Myrmicini. Additionally, t he formicine ant Camponotus ligniperda (tribe Camponotini) was analyze d as an outgroup species. Among all investigated species, the fragment had a variable length of approximate to 230-380 bp with only a few co nserved sequence elements. The sequences of this fragment were perfect ly identical within four palearctic populations of Leptothorax acervor um indicating that intraspecific variation is rather low. Within the s pecies of Tetramoriini (including Anergates atratulus) 94.1% of sequen ce positions were identical, 95.6% within the species of the Leptothor ax s.str.-group and 64.6% within the species of the Myrafant-group. Ph ylogenetic analysis reveals that the social parasites Harpagoxenus sub laevis, Doronomyrmex goesswaldi, D. kutteri and D. pacis, Chalepoxenus muellerianus as well as Strongylognathus alpinus and Teleutomyrmex sc hneideri are most closely related to the groups of their respective ho st species, which generally confirms the taxonomical classifications o f the subfamily Myrmicinae based on morphological criteria. The taxono mical positions of the species A. atratulus has as yet been uncertain, however, sequence comparison of the ITS-1 fragment leads to the concl usion that A, atratulus rather belongs to the tribe Tetramoriini than to the Solenopsidini.